Tube tapering arrangement



May 20, 1969 up, SELLARS TUBE TAPERING ARRANGEMENT Filed June 1. 1965 Sheet INVENTOR.

LEONARD D. SELLARS ATTORNEYS May 20, 1969 o. SELLARS 7 5 TUBE TAPERING ARRANGEMENT Fil ed June 1, 1965 Sheet .11. of 8 INVENTOR. LEONARD D. SELLARS BY Z ATTORNEYS May 20, 1969 r L..D. SELLARS TUBE TAPERING ARRANGEMENT Sheet File'd June 1, 1965 FIG. 4

FIG. 6

INVENTOR.

LEONARD D. SELLARS ATTORNEYS May 20, 1969 L. D. SELLARS TUBE TAPERING ARRANGEMENT Sheet 4 0118 Filed June 1, 1965 FIG. 23

INVENTOR.

LEONARD D. SELLARS FIG. 24

ATTORNEY:

May 20, 1969 L. D. SELLARS TUBE TAPERING ARRANGEMENT Sheet Filed June 1, 1965 INVENTOR.

LEONARD D. SELLARS ATTORNEYS M y 0, 1969 L. D. SELLARS 3,444,715

TUBE 'TAPERING ARRANGEMENT Filed June 1. 1965 Sheet 7 of 18 FIG. l3

INVENTOR.

LEONARD D. SELLARS BYKW? Sheet 8 of 18 Filed June 1, 1965 INVENTOR.

LEONARD D. SELLARS FIG. 26

ATTORNEYJ 1969 u... D.SELLARS I 3,444,715

TUBE TAPERING ARRANGEMENT Sheet 9 01 18 Filed June 1. 1965 FIG. 32

FIG. l8

FIG. 20

INVENTOR.

LEONARD D. SELLARS ATTQR NEYJ MayZO, 1969 L. o. SELLARS 3,444,715 I TUBE TAPERING ARRANGEMENT Sheet 10 or 18 Filed June 1, 1965 ll? H6 I I I I I2 I I I I I l32 I I I I I I I I I I I I FIG. 25

INVENTOR.

LEONARD D. SELLARS BY I If 6 ATTORNEYS May 20, 1969 1.. b. SELLARS TUBE TAPERING ARRANGEMENT Sheet 1/ of 18 Filed Juno 1. 1965 INVENTOR.

LEONARD D. SELLARS FIG. 33

May 20, 1969 L. D'L SELLARS TUBE TAPEf iI NG ARRANGEMENT Sheet 41 or 11! Filed. June 1. 1965 INVENTOR. LEONARD D. SELLARS BY f} 2 FIG. 34

May 20, 1969 L. o. SELLARS TUBE TAPERING ARRANGEMENT Sheet A or 18 Filed June 1, 1965 m Kw M M m & IMVT... m m w INVEN TOR. LEONARD D. SELLARS FIG. 35

ATTORNEYS Sheet /4 D. SELLARS" INVENTOR.

LEONARD D. ELLARS ATTORNEYS May 20, 1969 Filed June 1, 19 65 FIG. 36

May 20, 1969 L. D. SELLARS TUBE TAPERING ARRANGEMENT Sheet 1 of 15 Filed June 1. 1965 FIG. 37

INVENTOR.

LEGIARD D. SELLARS BY 7 4w ATTORNEYS H May 20,1969 L. o. SELLARS TUBE TAPERING ARRANGEMENT sum /6 e: 18

Filed Juno 1. 1965 FIG. 38

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United States Patent 3,444,715 TUBE TAPERING ARRANGEMENT Leonard D. Sellars, Rolling Hills, Califi, assignor to Precision Sheet Metal, Inc., Los Angeles, Calif., a corporation of California Continuation-impart of application Ser. No. 332,473,

Dec. 23, 1963. This application June 1, 1965, Ser.

Int. Cl. B21d 22/00, 7/00; B21c 3/12 US. CI. 72-84 22 Claims ABSTRACT OF THE DISCLOSURE This application is a continuation-in-part of my copending patent application Ser. N0. 332,473, filed Dec. 23, 1963, for Tube Tapering Arrangement, now abandoned.

This invention pertains to tube forming, and in particular to imparting a taper to a tube.

Frequently it becomes necessary to taper tubes at various portions or throughout their lengths. One use for such tubes is in the construction of rocket motors. There it may be required to assemble a large number of the tubes around the periphery of the motor with each of the tubes being tapered. Often the tubes are of varying contour, having a relatively small diameter at some portions, while others are enlarged. Tolerances are extremely exacting for such work, and each tube must be given a precise dimension. Generally, a constant wall thickness is specified regardless of the outside diameter given the tube. In other instances it may be necessary to vary wall thickness as well as outside diameter. The materials from which these tubes are constructed frequently are those that are particularly difiicult to form, such as the harder stainless steel alloys on one hand or metals that are very soft on the other.

In the past it has been proposed to provide a pair of opposed dies having tapered grooves that together define an opening through which the tube is passed to reduce its dimension. This means that rotation of the dies will vary the opening that they provide. As the tube is forced through the dies, a tension force may be applied to the tube, and it is rotated during this time as well.

While the use of rollers that define tapered grooves through which the tube is passed is adequate in some cases, there are certain tube tapering operations that cannot be accomplished satisfactorily in this manner. Inherently, in the use of such rollers there is a rubbing of the tube on the periphery of the groove as it is rotated relative to the dies. In most designs it is considered necessary to provide a relief at the edges of the grooves where one tapered groove joins the other. This results in corners that can dig into the tube as it is compressed and rotated within the aperture defined by the tapered grooves. Frequently, a galling of the tube results, a condition aggravated in imparting extreme tapers and with certain metals that are difiicult to contour. Consequently, either the tube cannot be tapered at all or the scrappage rates become 3,444,715 Patented May 20, 1969 "ice prohibitively high. Moreover, reduction in tube wall thickness has not been feasible with prior techniques.

The present invention overcomes the difliculties en countered with the tapered groove type of forming rollers by utilizing a fundamentally different approach. The aperture through which the tube is drawn is defined by freely rotatable annular rollers, larger in internal diameter than the outside of the tube, which are both offset and tilted with respect to the axis of the tube. Two or more of these rollers are utilized, with a preferred embodiment employing three to six or more of the offset rollers. By being laterally displaced and tilted at an acute angle with respect to the tube axis, it is possible for these rollers to define substantially a cylindrical aperture for the tube while engaging the tube throughout the major portion of its periphery. The forming rollers rotate with the tube and, consequently, burnish rather than gall the tubes surface. Sharp edges are entirely absent. Tube size is determined by the amount of tilt and offset which the annular rollers are given.

The invention may be constructed to include a means for gripping either end of a tube, rotating the tube and applying a tension to it. A carriage is movable axially with respect to the tube and carries with it a housing. Within the housing are several plates which contain the bearings that in turn mount the annular forming rollers. The plates are laterally movable, with alternate plates being shifted in one dir ction while the plates between them are moved oppositely. At the same time, the plates are tilted, thereby also tilting the forming rollers with them. The tube extends through the forming rollers and, as the carriage moves, the tube is contoured to a smaller diameter. If desired, the wall thickness of the tube can be controlled by forging inwardly with the annular rollers against a tapered mandrel within the tube.

Therefore, it is an object of this invention to provide an improved arrangement for imparting a taper to a tube.

A further object of this invention is to provide an arrangement for forming tubes to extreme tapers and close tolerances.

Another object of this invention is to reduce the diameter of tubes without impairing their surface finish or tending to flatten or otherwise distort the tubes during the forming process.

An additional object of this invention is to provide a tube tapering ararngement in which there are no sharp edges or corners present on the forming members to damage the tubes surface.

A still further object of this invention is to provide a tube tapering arrangement in which the tube is rotated during forming, and the forming members rotate with the tube.

Yet another object of this invention is to provide an arrangement that can reduce the wall thickness as well as taper the diameter of a tube.

These and other objects will become apparent from the following detailed description taken in connection with the accompanying drawing in which:

FIGURE 1 is a top plan view of the overall arrangement for contouring tubes in accordance with this invention;

FIGURE 2 is a side elevational view of the arrangement of FIGURE 1;

FIGURE 3 is an end elevational view of a pair of annular rollers, illustrating the manner in which a tube is constrained for forming in accordance with this invention;

FIGURE 4 is a perspective view, illustrating how three rollers may be associated together in the forming Operation; V

FIGURE 5 is an axial sectional view of three forming rollers mounted in bearings and support plates;

FIGURE 6 is a view similar to FIGURE with the rollers tilted;

FIGURE 7 is a perspective view of the inner tilt housing that contains the rollers and their SuppOrt plates;

FIGURE 8 is a top plan view of the tilt housing with the roller plates received therein;

FIGURE 9 is a perspective View of one of the end members of the tilt housing;

FIGURE 10 is a perspective View Of the other end member of the tilt housing;

FIGURE 11 is a transverse sectional view of the carriage and associated elements where the tube is engaged and contoured;

FIGURE 12 is an enlarged transverse sectional view through the outer housing and the tilt housing, with one of the outer roller plates removed for clarity;

FIGURE 13 is a side elevational view, partially broken away, of the tube contouring arrangement;

FIGURE 14 is an enlarged fragmentary sectional view illustrating one of the spring-loaded return pins for a roller plate;

FIGURE 15 is a perspective view of the plunger for imparting translaional movementt to the outer roller plates;

FIGURE 16 is a perspective view of the cross pin that is carried by the plunger illustrated in FIGURE 15;

FIGURE 17 is an elevational view of the assembly for imparting translational movement to the outer roller plates as received in the housing;

FIGURE 18 is a perspective view of the side plate of the outer housing which receives the assembly for translationally moving the outer roller plates;

FIGURE 19 is a side elevational view of one of the ouer roller plates;

FIGURE 20 is an enlarged end elevational view of the plate of FIGURE 19, illustrating the socket for the bearing that moves the plate laterally;

FIGURE 21 is a side elevational view of the center roller plate;

FIGURE 22 is an end elevational view, partially broken away, of the plate of FIGURE 21;

FIGURE 23 is a sectional view taken along line 2323 of FIGURE 12 but with the tilt housing in a rotated position;

FIGURE 24 is a sectional view taken along line 2424 of FIGURE 12 with the tilt housing erect;

FIGURE 25 is a side elevational view of the tube contouring arrangement, taken from the opposite side from the view of FIGURE 13;

FIGURE 26 is an end elevational view, partially in section, of a modified roller plate construction which positions the forming rollers axially close together;

FIGURE 27 is a perspective view of a modified cross pin for providing differential translational positions of the two outer roller plates;

FIGURE 28 is a side elevational view of the pin of FIGURE 27 with the thrust bearings in place;

FIGURE 29 is a sectional view of a tube tapered by the use of rollers in accordance with this invention;

FIGURE 30 is a sectional view of the tube of FIGURE 29 with a mandrel inserted preparatory to tapering the tube wall thickness;

FIGURE 31 is a sectional view similar to FIGURE 30 after the wall of the tube has been tapered;

FIGURE 32 is a sectional View of a modified roller having a different contour on the surface which engages the tube;

FIGURE 33 is a side elevational view of a different embodiment of the invention in which the rollers are given progressive increments of lateral displacement and rotational movement;

FIGURE 34 is an end elevational view of the arrangement of FIGURE 33;

FIGURE 35 is an enlarged sectional view taken along line 35-35 of FIGURE 34;

FIGURE 36 is a view similar to FIGURE 35 but with 4 the mechanism shifted to provide displacement of the forming rollers;

FIGURE 37 is a sectional view taken along line 37-37 of FIGURE 35;

FIGURE 38 is a sectional view taken along line 38-38 of FIGURE 36;

.FIGURE 39 is a front elevational view, partially broken away, illustrating one of the roller plates;

FIGURE 40 is a sectional view taken along line 4040 of FIGURE 39;

FIGURE 41 is an enlarged fragmentary sectional view taken along line 41-41 of FIGURE 39;

FIGURE 42 is a schematic illustration showing the increments of rotation given to the forming rollers; and

FIGURE 43 is a perspective view Showing both the progressive lateral displacement and progressive amounts of rotation of the roller plates, with the plates being shown separated and the amounts of movement slightly exaggerated for the purpose of illustration.

With reference to the drawing, the general layout of a machine incorporatng the principles of this invention may be seen by reference to FIGURES 1 and 2. This includes a stationary bed 1 provided with longitudinally extending ways 2. A carriage 3, which supports a housing 4, is movable along the path defined by the ways. The carriage is moved by hydraulic cylinder 5, having a piston rod 6 that at its distal end carries a gear 7. This gear is opposed between a fixed rack 8 and a movable rack 9 that is slidable longitudinally of the bed 1. The rack 9 connects to the carriage 3. Consequently, when the piston rod 6 is extended or retracted, the gear 7 operating between the fixed rack 8 and the movable rack 9 causes the carriage to move along the ways 2 of the bed of the machine. This is a particularly low cost, yet fully satisfactory, carriage-moving arrangement, being far simpler than the conventional feed-screw type of design. The use of the fiixed and movable racks in effect doubles the stroke of the piston of the hydraulic cylinder 5. By utilizing the two racks, the carriage is caused to move twice as far as the movement imparted to the piston rod 6.

The machine also includes chucks 11 and 12 on opposite sides of the carriage 3. The chuck 11 is rotatable by motor 13, while the other chuck 12 is rotated equally and simultaneously with the chuck 11. In order to accomplish this rotation of the second chuck, the drive shaft 14 from the motor 13 mounts a pinion 15 driving a gear 16, which in turn rotates an elongated shaft 17. At the opposite end of shaft 17 is a pinion 18, which is identical to the gear 16 and in turn drives gear 19 on the shaft 20 that mounts the chuck 12. With the gear 19 being the same as the pinion 15, it can be seen that the rotation of motor 13 causes the two chucks to turn together.

The chuck 12 is movable axially and, consequently, includes a spline 21 that extends through the gear 19 and mates with a comparable recess in the gear. The gear 19 is restrained by bearings 22 and 23 and hence remains axially fixed. Thrust bearing 24 is carried at the end of shaft 20 and received within a connector 25 where it is held between wall 26 and flange 27. The connector 25 is carried by a piston rod 28 that extends to hydraulic cylinder 29. Therefore, by extension or retraction of the rod 28 the chuck 12 can be caused to move toward or away from the chuck 11. The gear 19 floats on the shaft 20 as this movement takes place.

The tube 30 to be tapered is gripped by the chucks 11 and 12 and extended through the housing 4, where the contouring takes place. During the forming operation the tube is rotated by the motor 13 and held under tension by means of the hydraulic cylinder 29. The carriage 3 is advanced from a position adjacent the chuck 11 to a location near the chuck 12, progressively contouring the tube as this movement takes place.

The basic principle of the tube contouring i illustrated schematically in FIGURE 3. Here there may be seen 

